Application is made for a conference (R-13) grant to hold a symposium and workshop on the opportunistic parasite Pneumocystis carinii at Bristol University, Bristol, England concurrently with the 41st Annual Meeting of The Society of Protozoologists. The aim is to mix basic scientists working on the immunology, protein chemistry and molecular biology of this organism with pharmacologists and physicians interested in its chemotherapy. A special feature will be a round-table discussion with eminent scientists familiar with other areas of protozoal and parasitic culture with the aim of improving the present unsatisfactory culture methods.